Fuel reformers can be used to convert alcohol fuels into gaseous fuels (reformates) to fuel an engine. For example, an ethanol reformer can reform ethanol into a reformate gas comprising hydrogen (H2), carbon monoxide (CO), and methane (CH4) for combustion in an engine.
The inventors herein have recognized that engines with fuel reformers may be fueled with a variety of different fuels with varying alcohol content, e.g., flexible fuel engines. For example, a flexible fuel engine may be fueled with ethanol, ethanol-gasoline blends such as E85, E50, etc., or gasoline. In such engines, operation of a fuel reformer may degrade when the alcohol content of the fuel is too low. For example, if a reformer is supplied with a variable alcohol blend from one fuel refill to the next, a significant amount of non-reformed fuel may be output by the reformer.
In one example approach, the above issues can be at least partially addressed by a method for operating an engine, comprising: reforming a fuel into a gaseous fuel including H2 when an alcohol content of the fuel is above a threshold; and not reforming a fuel into a gaseous fuel including H2 when an alcohol content of the fuel is above the threshold.
In another example approach, the above issues can be at least partially addressed by a method for operating an engine with an alcohol reformer which reforms a fuel into a reformate including H2, the method comprising: adjusting an operating condition of the alcohol reformer based on an alcohol content of the fuel.
In this way, operation of a fuel reformer employed by an engine may be tailored based on an alcohol content of a fuel and degradation of fuel reformer operation reduced.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.